Greases



UNITED STATES PATENT osslcs ssossss J 1 oaassas Alfred W. Weitkamp,

porstion of Indiana No Drawing.

This invention relates to improvements in the manufacture of rosin oil, and more particularly to an improved method of preparing rosin oil suitable for use in the manufacture of grease.

The destructive distillation of rosin yields distillates of viscous oils known in the trade as "rosin oils. The distillation may be carried out by fire in the usual type rosin still or by fire in the presence of superheated steam. The fractions usually recovered are rosin spirits, distilling at about 160 0., light oil distillates at about 200 0., "kidney oil distilling at about 250 0., and "bloom" oil distilling at about 270 C. Heretofore, it has been the practice in the manufacture of greases, particularly the so-called sett greases, to saponify a mixture of rosin oil and petroleum oil of suitable viscosity, with calcium oxide or slacked lime under such conditions to produce a grease having the desired setting characteristics. The rosin oil used is the so-called kidney oil, but sometimes the so-called "bloom oil is used. Rosin oil usually employed for this purpose contains about 40-50% abietic acid. Although rosin, from which the rosin oil is produced, contains more than90% abietic acid, rosin per se cannot be employeddn the manufacture of grease since it will not set properly; therefore, since the value of rosin oil as a grease component is in its acid content of about 40-50%, the re maining 50-60% of the neutral oilin the rosin oil is not utilized in the preparation of the soap. Furthermore, the residuum remaining after distilling the rosin oil is not used in the grease making process, and therefore may be considered wasted.

In order to utilize the rosin more fully, it has been the practice heretofore to form the rosin oil in situ by heating a mixture of petroleum oil and rosin at a temperature of about 500 F. to about 515 F. for such a period that the rosin oil produced will give to the grease, upon saponification with lime, the proper setting and consistency characteristics. In order to obtain a rosin oil having the desired characteristics, it is usually necessary to heat the mixture of rosin and oil for a period of about 24 to 44 hours or longer. The duration of heating is determined by sampling the rosin oil periodically, preparing small mixes of grease therefrom and determining the setting time and penetration thereof. The reaction is considered complete when a sett grease prepared with lime, mineral oil and the sampled rosin oil sets to a solid gel in 24 to 40 seconds and has an unworked penetration of 150 to 170 by the A. S. T. M. cone penetrometer test at a soap con- Hammond, lnd.. assignor to Standard Oil Com pany, Chicago, 111., a cor- Application November 20, 1946, Serial No. 711,193

, able for use in the manufacture of cold sett greases. Another object of the invention is to provide an improved method of preparing sett greases. Another object of the invention is to provide a method of treating rosin to produce rosin oils having the property of imparting to greases desirable setting characteristics. Another object of the invention isto provide a method of preparing rosin oils without substantial decarboxylation. Another object of the present invention is to provide a method of rapidly forming rosin oils from rosin. Other objects and advantages of the invention will become apparent from the following description thereof.

I have discovered that the foregoing objects can be attained by heating rosin or a mixture of from about 5% to about and specifically from about 20% to 50% of a hydrocarbon oil with from about 10% to about and preferably from about 50% to about 80% rosin in the presence of a member of the sulfur group, namely a sulfur, selenium or -tellurium, and particularly sulfur at a temperature of from about 350 F. to about 500 F., and preferably from about 400 F. to about 450 F. for a period of time within the range of from about 0.5 hour to about 12 hours. and preferably from about one hour to about 9 hours, the optimum time being dependent upon the temperature and amount of catalyst used. The catalyst can be used in amounts ranging from about 0.1% to about 5% by weight, and preferay f ut 0.2 to about 1.0% by weight. The mineral 011 does not take part in the actual conversion of the original rosin to rosin oil but -merely serves as a diluent for the. rosin which are mixtures'of calcium soaps of rosin acids and various grades of mineral lubricating oils. Sott greases, which may contain from about 5% to acaaaaa for the lubrication of rough. heavy bearings operating at low speeds, and are used extensively in the logging industry where a relatively cheap grease is required for theilubrication of skidways. Theyare also used in the lubrication of gears. .The following example illustrates one method of applying the present invention to the preparation of so-called sett greases. A mixture of 65% Krosin and 35% of a distillate mineral oil having a Saybolt Universal viscosity at100 F., of about 80 to 85 seconds is mixed with 0.25 to about 1.0% (by weight) elemental sulfur and the mixture heated to a temperature ofabout 450% F. Periodically samples are withdrawn from the heated mixture and mixed with about 3% slacked lime, 76% mineral oil and 6% water and the time for the mixture toset or gel noted. If this mixture sets or gels in 20 to 40 seconds and has an unworked penetration of 150-170, the heating is stopped and the finished rosin oil either pumped to storage or used at once in the preparation of lubricating greases. Depending upon the amount of sulfur used, it will be found suflicient usually to heat the rosin oil mixture at 450 F. for one to 9 hours. By methods heretofore used in commercial operation, about 44 hours would be required for heating the rosin-oil mixture to obtain a rosin oil which would produce a calcium rosin soap having the desired setting and penetration characteristics.

The advantage of the present invention is clearly demonstrated by the data in Table I in which the A. S. T. M. penetration at 7'7 F. valuesand setting time for sett greases prepared from oil and rosin mixtures heated in the presence of 0.5% and 1.0% sulfur at 450 F. for various periods of time are compared with sett greases from rosin oils prepared by simply heating mineral oil and rosin at 500 F. over long periods of time in the absence of a catalyst.

Table I A. S. T. M. Penetration at 77 F. and Sett Time in Seconds Per Cent (Weight) Sulfur Heating Period,

Hours 0.0% l 0.5% 1.0%

Penetra- Sett Penetra- Sett Penetra- Sett tion Time tion Time' tion Time Oil-Resin Composition:

I 35% neutral pale petroleum il+65'7 K rosin heated at 500 F. 1 35% neutral pale petroleum oil+65 OK rosin heated at 450 F. The sett greases used in obtaining the above data were prepared to give an A. S. T. M. penetration at 77 F. of 150 to 170 with a gel or setting time of to 40 seconds. As shown by the above 'data using 1% sulfur in the preparation-of the rosin oil, a sett grease meeting these specifications can be prepared by heating the mixture for 1 to 3 hours; whereas, with a,% sulfur, a heating period of 4 to 9 hours is required. When no sulfur was used in the preparation of the rosin oil,

sett greases having the penetration within the specified range were obtained after heating for '7 to 12 hours; however, the greases had a setting or gelling period outside of the specified range of 20 to seconds.

A further advantage of preparing rosin oils in accordance with the present invention is that the rosin oil contains a much higher acid content than rosin oils prepared by prolonged heating. Since rosin oils having the desired characteristics are obtained much more rapidly and at lower temperatures when prepared in the presence of the sulfur catalyst than when prepared in the absence of the catalyst, there is a material improvement in the acid content of the former. This is shown by the data in Tabl II, in which are tabulated the percent of rosin acid in mixtures of oil and rosin heated i the presence of sulfur and for along period of he and at a higher temperature in the absence of sulfur.

- Table II Percent Rosin Acid in Heated Producg, Per Heating Period, Hours gent (welght) 1 35% neutral pale petroleum oil+65% K rosin heated at 500 F. 1 35% neutral pale petroleum oil-+65% K rosin heated at 450 F. Original rosin acid content of K rosin-about 64%.

.Heating a mixture of oil and rosin at 450 F. in

the presence of 1% sulfur, produces in one to three hours a rosin oil having the desired setting and gelling characteristics; with sulfur heating from 4 to 9 hours produces a satisfactory rosin oil. However, heating the rosin oil in the absence of any sulfur requires about 44 hours at higher temperature to obtain a rosin 011 product which is satisfactory for forming a sett grease having the desired gelling and penetration characteristics. that with 0.5% and 1.0% sulfur the satisfactory rosin oil had an acid' content of about 62%.

However, in the preparation of rosin oil in the absence of sulfur, the acid content is reduced to about 46.2% in 14 hours of heating.

In commercial plant practice it has been possible to prepare rosin oil from a mixture of 35% mineral oil and K rosin which after about 44 hours heating at 500 F. has a rosin acid content .of 50%. A sett grease made from this rosin oil will set or gel in 25-40 seconds and have a penetration in the range of -170 at a lime soap content of 9.5%. The sett greases for which data are given in Table I were all made with the same rosin oil content but the soap content varied because of the change in acid content with dura- The data in Table II show tion of heating as shown in Table II. It is e'vl dent that for a given rosin oil content the batches made with sulfur gave harder greases. In practice this would result in substantial economy due to the use of less of the rosin oil. Also the sulfur containing examples gave desirably fast setting times which would permit packaging the finished greases with a minimum of delay, whereas, the rosin oil containing no sulfur gave soft greases which gelled slowly.

While I have described the invention in connection with the preparation of sett greases. the invention is not limited thereto, but is applicable to the preparation of rosin oils for use in the I preparation of greases in general. particularly those prepared by saponifying rosin oils with an,

alkali metal base, or an alkaline earth base such greases of the herein-described types. Additional lubricating assistants. such -as graphite, mica, etc. may also be employed.

The advantages of the herein-described invention over the previous methods are manifold. To state a few are the following: a reduction in the heating time for the oil-rosin mix of from 44 hours to 1 to 9 hours, to effect optimum rosin conversion, and the subsequent saving in time, labor and heat; the loss in rosin acid through decarboxylation at 490-500 1". in the present invention is much less than the loss obtained in heating for 44 hours by the old method. resulting in the need of less rosin oil to form a grease of specified consistency, and; a better colored product is obtained.

Although I have described my invention as applied to the preparation of greases. it will be understood that the catalytic disproportionation of rosin with sulfur, as the catalyst, in the manner herein described, has wider application. For example. disproportionated rosin, that is, rosin which has been hydrogenated and dehydrogenated without substantial decarboxylation, is

' widely used in the rubber industry.-

When used herein and in the appended claims, the percentages given are on a weight basis.

While I have described the preferred embodiments of my invention, it will be readily apparent to those skilled in the art that many variations and modifications may be made therein without departing from the spirit of the invention, the scope of which is limited solely by the appended claims.

I claim:

1. The method of preparing a rosin soap grease comprising heating a mixture of the hydrocarbon oil and unpolymerized rosin at a temperature of from about 350 F. to about 450 F. in the presence of from about 0.1 weight percent to about 1 weight percent of a catalyst selected from the class consisting of sulfur, selenium and tellurium but in the absence of a hydrogenation catalyst, for a time sufficient to produce a rosin oil having the property to produce, upon saponiiication. a grease having the desired setting and penetration characteristics and subsequently saponifying the mixture of oil and rosin so formed with a reagentselected from the class consisting of an alkaline "earth base. an alkali metal base, and mixtures thereof.

2. The method of preparing a rosin soap grease. comprising heating a mixture of hydrocarbon oil and unpolymerized rosin at a temperature of from about 350 F. to about 450 F. in the presence of about 0.25 weight percent to about 1.0 weight percent sulfur but in the-absence of a hydrogenation catalyst until a sample of the heated mixture forms upon saponiiication a grease having the desired setting and penetration characteristics, and then saponifying the body of the heated mixture with a base selected from the class consisting of an alkaline earth base, an alkali metal base, and mixtures thereof.

3. The method of preparing an alkaline earth rosin soap grease comprising heating a mixture of hydrocarbon oil and unpolymerized rosin at a temperature of from about 350 F; to about 450 F. in the presence of about 0.1 weight percent to about 1.0 weight percent sulfur. but in the absence of a hydrogenation catalyst, until the sample of the heated mixture forms upon dilution with mineral oil and saponification with an alkaline earth base a grease having the desired setting and penetration characteristics and then diluting with mineral oil and saponifying, the body of the heated mixture with an alkaline earth base. 1

4. The method of claim 3 in which the alkaline earth is calcium.

5. The method of preparing alkali metal rosin soap grease comprising heating a mixture of hydrocarbon oil and unpolymerized rosin at a temperature of from about 350 F. to about 450 F.

in the presence of from about 0.1 weight percent a to about 1.0 weight percent sulfur but in the absenceof a hydrogenation catalyst, for a time such that a sample of the heated mixture forms upon dilution with mineral oil and saponification with an alkali metal base a grease having the desired setting and penetration characteristics, and

then diluting with mineral oil and saponifying' the class consisting of an alkaline earth base, an

alkali metal base, and a mixture thereof, the improvement comprising heating a mixture of hydrocarbon oil and unpolymerized rosin with from about 0.1 weight percent to about 1 weight percent sulfur, but in the absence of the hydrogenation catalyst, at a temperature of from about 350 F. to about 450 F. fora time suflicient to produce rosin oil which upon dilution with mineral oil and saponiflcation will form a grease having the desired setting and penetration characteristics.

8. In the preparation of calcium rosin soap grease, wherein the rosin soap is prepared by saponifying rosin oil' with a calcium base,.the improvement comprising heating a mixture of hydrocarbon oil and unpolymerized rosin with from about 0.25% to about 1.0% sulfur, but in the absence of a hydrogenation catalyst, at a temperature of from about 400 F. to about 450 1'. for about from 1 hour to 9 hours and saponifying the resultant hydrocarbon oil and rosin oil mixture with a calcium base.

9. In the preparation of a grease containing from about 5% to about 25% calcium rosin soap.

4 wherein the rosin soap is prepared by reacting V but in the absence of a hydrogenation catalyst,

for about 1 to 9 hours, and subsequently saponifying the mixture of hydrocarbon oil and rosin oil formed with an excess of calcium hydroxide.

REFERENCES CITED The following referencesare of record in the file of this patent:

UNrrnEn STATES PATENTS Number Name Date Mariner Sept. 1, 1914 Low Oct. 16, 1917 Lister Dec. 21, 1937 Colgate Oct. 3, 1944 Borglln Sept. 10, 1946 Kalman Dec. 24, 1946 OTHER REFERENCES ComptesRendus, vol. 213, pages 793-796, Dec.

Naval Stores Review. page 15, Nov. 24, 1945. Zeiss: Chemical Reviews, pages 167-169 and 186, Feb..1948.- 

